US5176761A - Process for chemically treating aluminum work pieces - Google Patents
Process for chemically treating aluminum work pieces Download PDFInfo
- Publication number
- US5176761A US5176761A US07/775,825 US77582591A US5176761A US 5176761 A US5176761 A US 5176761A US 77582591 A US77582591 A US 77582591A US 5176761 A US5176761 A US 5176761A
- Authority
- US
- United States
- Prior art keywords
- exposing
- oxidizing agent
- aluminum
- structural component
- oxide coating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 title claims abstract description 13
- 229910052782 aluminium Inorganic materials 0.000 title claims abstract description 13
- 238000000034 method Methods 0.000 title claims description 19
- 238000000576 coating method Methods 0.000 claims abstract description 14
- 239000011248 coating agent Substances 0.000 claims abstract description 13
- 230000003647 oxidation Effects 0.000 claims abstract description 9
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 9
- 229910000838 Al alloy Inorganic materials 0.000 claims abstract description 7
- 239000002253 acid Substances 0.000 claims abstract description 7
- 229910052500 inorganic mineral Inorganic materials 0.000 claims abstract description 4
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims description 5
- 150000003863 ammonium salts Chemical group 0.000 claims description 2
- 159000000000 sodium salts Chemical group 0.000 claims description 2
- 238000005507 spraying Methods 0.000 claims description 2
- 239000007800 oxidant agent Substances 0.000 claims 6
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 claims 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims 2
- -1 peroxide disulfide Chemical class 0.000 claims 2
- 229910003252 NaBO2 Inorganic materials 0.000 claims 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 claims 1
- 229960002163 hydrogen peroxide Drugs 0.000 claims 1
- NVIFVTYDZMXWGX-UHFFFAOYSA-N sodium metaborate Chemical compound [Na+].[O-]B=O NVIFVTYDZMXWGX-UHFFFAOYSA-N 0.000 claims 1
- 230000001070 adhesive effect Effects 0.000 abstract description 5
- 230000001590 oxidative effect Effects 0.000 abstract description 5
- 239000000853 adhesive Substances 0.000 abstract description 4
- 238000004026 adhesive bonding Methods 0.000 abstract description 4
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 abstract description 3
- 239000002344 surface layer Substances 0.000 abstract description 2
- 238000005554 pickling Methods 0.000 description 2
- 238000011282 treatment Methods 0.000 description 2
- 230000002378 acidificating effect Effects 0.000 description 1
- ZCDOYSPFYFSLEW-UHFFFAOYSA-N chromate(2-) Chemical compound [O-][Cr]([O-])(=O)=O ZCDOYSPFYFSLEW-UHFFFAOYSA-N 0.000 description 1
- KRVSOGSZCMJSLX-UHFFFAOYSA-L chromic acid Substances O[Cr](O)(=O)=O KRVSOGSZCMJSLX-UHFFFAOYSA-L 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- AWJWCTOOIBYHON-UHFFFAOYSA-N furo[3,4-b]pyrazine-5,7-dione Chemical compound C1=CN=C2C(=O)OC(=O)C2=N1 AWJWCTOOIBYHON-UHFFFAOYSA-N 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 239000010410 layer Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 235000011007 phosphoric acid Nutrition 0.000 description 1
- 150000003016 phosphoric acids Chemical class 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J5/00—Adhesive processes in general; Adhesive processes not provided for elsewhere, e.g. relating to primers
- C09J5/02—Adhesive processes in general; Adhesive processes not provided for elsewhere, e.g. relating to primers involving pretreatment of the surfaces to be joined
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
- C23C22/06—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6
- C23C22/48—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 not containing phosphates, hexavalent chromium compounds, fluorides or complex fluorides, molybdates, tungstates, vanadates or oxalates
- C23C22/56—Treatment of aluminium or alloys based thereon
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J2400/00—Presence of inorganic and organic materials
- C09J2400/10—Presence of inorganic materials
- C09J2400/16—Metal
- C09J2400/166—Metal in the pretreated surface to be joined
Definitions
- the invention relates to a process for chemically treating work pieces made of aluminum or aluminum alloys to produce surfaces having an oxide coating needed for an adhesive bond with surface layers or other structural components.
- the pickling-process is negatively criticized due to the dangers that it can cause for the environment. Specifically, because the chromate necessary for the pickling should not be discharged into the environment after it has been used. In addition, energy is needed in the pickling process to heat the bath.
- the surface of aluminum and aluminum alloy components is oxidized to form an aluminum oxide coating by exposing the respective surface, e.g. by immersion for a specific time duration in a combination bath of an inorganic mineral acid and an oxidation medium, said time duration being sufficient to form the oxide coating.
- the process of the invention has the advantage of working with inexpensive chemicals, and also does not need any additional energy, since the combination bath works best at room temperature.
- Sulfuric or phosphoric acids are preferably used as the inorganic mineral acid.
- Peroxide-disulfide, such as the ammonium salt, or perborate, such as sodium salt are preferably used as the oxidation medium.
- a time duration for the exposure of about thirty minutes has been found to be practical and sufficient to obtain a satisfactory oxide coating.
- the combination bath should have an acid concentration of at least 3 mol per liter and an oxidation medium concentration of at least 0.3 mol per liter.
- the treatment of aluminum or aluminum alloy structural components according to the invention leads to optimal surface conditions for the subsequent adhesive bonding, since the oxide coating on the aluminum components ensures an excellent adhesion stability for the adhesive bonding.
- the present process as compared to known processes, can be carried out with greater reliability, and it does not produce any disposal problems, the present bath is chromate-free.
- the process of the invention may be carried out with hydrogen peroxide (H 2 O 2 ) as the oxidation medium.
- H 2 O 2 has a lower redox potential than the above mentioned oxidation media.
- a solution of hydrogen peroxide in an acidic carrier has a rather high decomposition rate. As a result, the effort and expense for properly controlled operating conditions may not be preferable.
- the pretreatment according to the invention may also be achieved by the application of a combination oxidizing paste or by spraying a combination oxidizing solution onto the surfaces of the structural components to be oxidized.
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Chemical Treatment Of Metals (AREA)
- Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
- Adhesives Or Adhesive Processes (AREA)
Abstract
Surfaces of structural components made of aluminum or aluminum alloys are chemically treated to produce an aluminum oxide coating for improved adhesive bonding to other components or to other surface layers. The oxidizing is accomplished by exposing the surface to be oxidized to a combination bath of an inorganic mineral acid and an oxidation medium for a specific time duration, so that an oxide coating is produced on the surface of the structural components, as a prerequisite for a good adhesion stability of adhesive bonds to be formed after oxidizing.
Description
The invention relates to a process for chemically treating work pieces made of aluminum or aluminum alloys to produce surfaces having an oxide coating needed for an adhesive bond with surface layers or other structural components.
In the production of structural components by adhesive bonding of individual components of aluminum or aluminum alloy, it is necessary that the surfaces of these components are pretreated to assure the required bonding strength. In this pretreatment of the aluminum components, the component surfaces are covered with an oxide coating, which is a necessary prerequisite for the desired adhesion stability of the adhesive bond. Until now, it was customary to produce the oxide film on the aluminum components by means of a so-called pickling-process, which works on the basis of chromic acid which provides good pretreatment coatings with strong adhesive properties.
The pickling-process, however, is negatively criticized due to the dangers that it can cause for the environment. Specifically, because the chromate necessary for the pickling should not be discharged into the environment after it has been used. In addition, energy is needed in the pickling process to heat the bath.
In view of the above it is the aim of the invention to achieve the following objects singly or in combination:
to provide a process for chemically treating structural components made of aluminum or aluminum alloy to form an aluminum oxide coating on the surface of such components, whereby the process takes into account the demands for lower environmental burdens;
to provide an oxidizing process that does not require additional energy for producing an adequate oxide layer on aluminum structural components; and
to assure a tenacious bond between the oxide coating and the aluminum on the one hand and the oxide coating and the adhesive on the other hand.
According to the invention the surface of aluminum and aluminum alloy components is oxidized to form an aluminum oxide coating by exposing the respective surface, e.g. by immersion for a specific time duration in a combination bath of an inorganic mineral acid and an oxidation medium, said time duration being sufficient to form the oxide coating.
The process of the invention has the advantage of working with inexpensive chemicals, and also does not need any additional energy, since the combination bath works best at room temperature.
Sulfuric or phosphoric acids are preferably used as the inorganic mineral acid. Peroxide-disulfide, such as the ammonium salt, or perborate, such as sodium salt are preferably used as the oxidation medium.
A time duration for the exposure of about thirty minutes has been found to be practical and sufficient to obtain a satisfactory oxide coating.
The combination bath should have an acid concentration of at least 3 mol per liter and an oxidation medium concentration of at least 0.3 mol per liter.
The treatment of aluminum or aluminum alloy structural components according to the invention, leads to optimal surface conditions for the subsequent adhesive bonding, since the oxide coating on the aluminum components ensures an excellent adhesion stability for the adhesive bonding. The present process, as compared to known processes, can be carried out with greater reliability, and it does not produce any disposal problems, the present bath is chromate-free.
As a further example, the process of the invention may be carried out with hydrogen peroxide (H2 O2) as the oxidation medium. However, H2 O2 has a lower redox potential than the above mentioned oxidation media. More specifically, a solution of hydrogen peroxide in an acidic carrier has a rather high decomposition rate. As a result, the effort and expense for properly controlled operating conditions may not be preferable.
The pretreatment according to the invention may also be achieved by the application of a combination oxidizing paste or by spraying a combination oxidizing solution onto the surfaces of the structural components to be oxidized.
Any of the treatments disclosed herein are followed by a proper rinsing with water.
Although the invention has been described with reference to specific example embodiments, it will be appreciated that it is intended to cover all modifications and equivalents within the scope of the appended claims.
Claims (7)
1. A process of producing an oxide coating on a surface of a structural component made of one of aluminum and aluminum alloys, comprising the following steps:
(a) preparing an oxidizing agent by mixing an inorganic mineral acid selected from the group consisting of sulfuric acid and phosphoric acid and an oxidation medium selected from the group consisting of peroxide disulfide, perforate, and hydrogenperoxide, said oxidizing agent having an acid concentration of at least 3 mol per liter and an oxidation medium concentration of at least 0.3 mol per liter,
(b) exposing said surface of said structural component to said oxidizing agent at room temperature for a length of time sufficient to form said oxide coating, and
(c) rinsing said surface.
2. The process of claim 1, wherein said peroxide disulfide is ammonium salt (NH4)2 S2 O8.
3. The process of claim 1, wherein said perborate is sodium salt NaBO2 H2 O2 3H2 O.
4. The process of claim 1, wherein said oxidizing agent is formed as a bath having said acid concentration of at least 3 mol per liter and said concentration of said oxidation medium of at least 0.3 mol per liter, and wherein said step of exposing is performed by immersing said structural component in said bath.
5. The process of claim 1, wherein said step of exposing this performed for about 30 minutes.
6. The process of claim 1, wherein said step of exposing is performed by applying a paste of said oxidizing agent onto said surface of said structural component.
7. The process of claim 1, wherein said step of exposing is performed by spraying a solution of said oxidizing agent onto said surface of said structural component.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4032214A DE4032214A1 (en) | 1990-10-11 | 1990-10-11 | METHOD FOR CHEMICAL TREATING WORKPIECES FROM ALUMINUM |
| DE4032214 | 1990-10-11 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US5176761A true US5176761A (en) | 1993-01-05 |
Family
ID=6416048
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US07/775,825 Expired - Lifetime US5176761A (en) | 1990-10-11 | 1991-10-11 | Process for chemically treating aluminum work pieces |
Country Status (3)
| Country | Link |
|---|---|
| US (1) | US5176761A (en) |
| EP (1) | EP0480141A1 (en) |
| DE (1) | DE4032214A1 (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2409271A (en) * | 1943-03-22 | 1946-10-15 | Welding Research Inc | Process for cleaning aluminum |
| GB1140052A (en) * | 1966-04-07 | 1969-01-15 | Foseco Int | Treatment of aluminium and aluminium alloy powders |
| GB2125833A (en) * | 1982-08-11 | 1984-03-14 | Bnf Metals Tech Centre | Conversion coatings |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1502910A (en) * | 1922-08-11 | 1924-07-29 | Dilas Harry | Combined candy box and receptacle file |
| US4373050A (en) * | 1966-06-01 | 1983-02-08 | Amchem Products, Inc. | Process and composition for coating metals |
| US3586568A (en) * | 1967-07-26 | 1971-06-22 | Hooker Chemical Corp | Process for bonding elastomeric materials to metals |
| CH540350A (en) * | 1970-05-28 | 1973-08-15 | Ito Hikaru | Chemical oxide formation on aluminium (alloys) - using soln contg hydroxide former and dehydrating agent |
| JPS5313172B2 (en) * | 1973-06-14 | 1978-05-08 | ||
| GB1502910A (en) * | 1975-12-08 | 1978-03-08 | Gutehoffnungshuette Ag | Method of producing a lubricant carrier coating |
| JPS63172799A (en) * | 1987-01-12 | 1988-07-16 | 日本パ−カライジング株式会社 | Aluminum surface cleaner |
| GB8906160D0 (en) * | 1989-03-17 | 1989-05-04 | Alcan Int Ltd | Surface preparation for aluminium |
-
1990
- 1990-10-11 DE DE4032214A patent/DE4032214A1/en not_active Ceased
-
1991
- 1991-08-09 EP EP91113417A patent/EP0480141A1/en not_active Withdrawn
- 1991-10-11 US US07/775,825 patent/US5176761A/en not_active Expired - Lifetime
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2409271A (en) * | 1943-03-22 | 1946-10-15 | Welding Research Inc | Process for cleaning aluminum |
| GB1140052A (en) * | 1966-04-07 | 1969-01-15 | Foseco Int | Treatment of aluminium and aluminium alloy powders |
| GB2125833A (en) * | 1982-08-11 | 1984-03-14 | Bnf Metals Tech Centre | Conversion coatings |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0480141A1 (en) | 1992-04-15 |
| DE4032214A1 (en) | 1992-05-21 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| AS | Assignment |
Owner name: DEUTSCHE AIRBUS GMBH, GERMANY Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:MATZ, CHRISTOPH;KOCK, ERICH;MUSS, VOLKER;REEL/FRAME:006194/0325 Effective date: 19910925 |
|
| STCF | Information on status: patent grant |
Free format text: PATENTED CASE |
|
| FEPP | Fee payment procedure |
Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
| FPAY | Fee payment |
Year of fee payment: 4 |
|
| FPAY | Fee payment |
Year of fee payment: 8 |
|
| AS | Assignment |
Owner name: DAIMLERCHRYSLER AEROSPACE AIRBUS GMBH, GERMANY Free format text: CHANGE OF NAME;ASSIGNOR:DEUTSCHE AIRBUS GMBH;REEL/FRAME:010977/0943 Effective date: 19981117 |
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| FPAY | Fee payment |
Year of fee payment: 12 |